In an ordinary electroplating, an object to be plated is placed as cathode in the plating bath and an anode is placed in the same bath with some distance from the cathode. The plating is accomplished by applying electricity for the external power source. In this method, the current distribution will vary depending on the shape of the object to be plated and the location of the anode. To make a homogeneous thickness of the metal plating, various techniques are used to make the current distribution homogeneous. To increase the plating speed, usually the current density is increased. Such an increase in the current density often produces adverse effect; uneven deposits and reduction of the current efficiency.
To avoid much adverse effect, relatively low rates or low current densities are being used in today's industrial process; for example 1 to 5 Amp./dm.sup.2 for copper, nickel and zinc plating and 20 to 50 Amp./dm.sup.2 for chromium plating which needs a high current and the plating rate is usually less than 1.0 .mu.m/min. For high speed plating, usually the electrolyte solution is forced to flow at a high speed between the two electrodes. This method results in uneven current distribution. The high speed plating with high speed electrolyte circulation often require large size equipment which is an obvious disadvantage.